1. Field of the Invention
The present invention relates to an apparatus for supporting an electric-component mounter and particularly to the art of reducing the vibration of a floor which supports the electric-component mounter.
2. Related Art Statement
There is known an electric-component ("EC") mounter which includes a circuit-substrate ("CS") supporting device, an EC supplying device, and an EC mounting device. Those devices are supported on a common base member which is provided on the surface of a floor. The EC mounting device receives, from the EC supplying device, ECs (e.g., electronic components) as elements of an electric circuit (e.g., an electronic circuit), and mounts the ECs on a CS (e.g., a printed circuit board) supported by the CS supporting device. In this sort of EC mounter, at least one of the EC mounting device, the CS supporting device, and the EC supplying device includes a movable member which is movable for transferring the ECs supplied from the EC supplying device or mounting the ECs on the CS. Therefore, when the ECs are mounted on the CS, the movable member is accelerated and decelerated and accordingly the base member is subjected to vibration. Since the base member is fixedly supported by the floor, almost all the vibrational energy is transmitted to the floor. Thus, not only the base member but also the floor are vibrated. The base member may be fixedly supported by the floor, in such a manner that the floor surface is covered with a leveling sheet formed of steel and the base member is placed on the leveling sheet via a plurality of leveling bolts. In this manner, the level at which the CS is conveyed, and the level at which the EC mounting device and the EC supplying device are provided, can be adjusted. In addition, the plurality of leveling bolts can be contacted with the floor surface at a substantially uniform pressure. Thus, the base member and the floor are connected to each other as if it were a unit. Thus, almost all the vibrational energy is transmitted to the floor.
If a rubber sheet is inserted between the leveling sheet and the floor, the vibrational energy which is transmitted to the floor can be more or less reduced by the elastic deformation of the rubber sheet. However, this reduction is not satisfactory. In a particular case, the frequency of the vibration exerted to the rubber sheet coincides with the natural frequency of the same. In this case, the rubber sheet resonates and the vibration is amplified.